Train-pipe vent-valve device.



w. v. TURNER.

TRAIN PIPE VENT VALVE DEVICE.

APPLICATION FILED MAY 9, 1910. 1,1 14,821 Patented 001;. 27, 1914.

Att'y.

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movable` abutment 9 dividing the nnrTEn sTaTEs PATENT oEErcE;

WALTER V. TURNER, OIF EDGEWOOD, PENNSYLVANIA, ASSIGNOE TO THE WESTING- HOUSE AIRBRAKE COMPANY, OF PITTSBURGH, PENNSYLVANIA, ACOR-PORATIONl OF PENNSYLVANIA.

TEAINFIPIE VENT-VALVE DEVICE.

Application filed May 9, 1910. Serial No. 560,235.

Specication of Letters Patent.

To all whom 'it may concern:

Be itknown that I, WALTER V. TURNER, a citizen of the United States, residing at Edgewood, `in the county of Allegheny and State of Pennsylvania, have invented new and useful improvementsI in Train-Pipe Vent-Valve Devices, of which the following is a specification.

This `invention relates to fluid pressure brakes and has for its principal object to provide an improved valve mechanism adapted upon a `sudden reduction in train pipe pressure to effect a local venting of the train pipe.

In the accompanying drawing; Figure 1 is a diagrammatic view of a car brake equipment with the improved vent valve mech: anism applied thereto; Fig. 2 a central sectional view of a vent valve mechanism embodying my improvement and showing the parts in normal position; Fig. 3 a fragmentary sectional view similar to Fig.` 2, showing the position initially assumed by the parts upon a sudden reduction in train pipe pressure; and Fig. 4 a similar View showing the position of the parts following that shown in Fig. 3.

The car brake equipment may comprise the usual train pipe 1, triple valve 2, auxiliary reservoir 8, brake cylinder 4, and branch pipe 5 leading from the triple valve to the train pipe, the improved vent valve mechanism 6 being preferably located at the juncture of said branch pipe with the train pipe 1, as shown in Fig. 1.

Figs. 2, 3, and 4 illustrate a preferred construction of the vent valve mechanism embodying my improvement comprising a casing 7 having an outer chamber 8 into which the train pipe l opens, so that said chamber forms part of the train pipe volume. The casing 7 is also provided with an inner piston chamber, containing a piston chamber into a chamber 10. having its capacity preferably enlarged by the addition of a small reservoir" 11, anda chamber 12 adapted to communicate with the train pipe chamber 8 through a passage containing a check `valve 13 adapted to prevent flow of air to said chamber from the train pipe. The movable abutment 9 has a stem 14:, the outer end of which is provided with a seating ring adaptedto normally engage a seat 15 and thereby control communication from the train plpe chamber 8 to an atmospheric ment 9 is provided a piston chamber for a piston 17 adapted in one position to engage a seat 18 provided at the end of the piston chamber and inthe opposite position to seat on a ring 19 and close communication from chamber 12 to the train pipe chamber 8. The `piston stem 14 is guided somewhat loosely in a bushing 20 having openings 21 and 22 therein, and a small annular groove 23 is provided onthe piston stem, which is adapted in the normal position of the parts to connect the opening 2l from the train pipe chamber 8 to the opening 22 which leads with the triple valve branch pipe 5. The end portion of the piston 17 which engages l the seat 18 is of less diameter than the piston :and a differential area 24C is thus afl'orded which is subject to the pressure in chamber .10, openings 25 being provided in piston casing 2G so as to connect said area with the `chamber 10. It desired, a coil spring 27 llnay be employed to assist in maintaining the abutment 9 in its normal position.

l In operation, upon charging the train pipe with `fluid under pressure, air flows ,from the train pipe chamber throughthe opening 21, groove 23, and opening 22 to the ftriple valve branch pipe 5, whence it is supplied to the triple valve to charge the automatic brake parts in the usual manner. Air also leaks around the loose stem 14; of the movable abutment 9 and charges chamber 10 and reservoir 11 to normal pressure. From chamber 10 air flows through a `feed groove 28 around abutment 9 to chamber 12, so that v.the fluid pressures on opposite sides of the *abutment become equalized, and as the seated area of the stem 14 is exposed to the atmospheric pressure of the vent port 1G, there is a differential area of the abutment 9 subject to fluid pressure in a direction tending to seat the vent valve stem 14. A restricted passage 29 in the stem 14 connects the space within the seated area of piston 17 subject to the unbalanced pressure of the fluid contained in the chamber 12, which tends to maintain same on the seat 18. The groove 23 is of suflicicnt cross section to permit of such flow from the triple valve to the r train pipe as required in making' service apwith the vent port 1G, so that said piston is exhaust port 16. Vithin the movable abuttained substantially equal and the same re- Y mains in its normal position. As the triple valve is thus normally connected to the train pipe only through a restricted opening, un-

desired movement of the triple valve toV en'iergency position under gradual reductions in train pipe pressure is prevented. Upon a sudden reduction in train pipe pressure, however, fluid from chamber 12 flows past check valve 13 to the train pipe at a greater rate than the feed groove 28 can take care of, so that the abutment 9 is shifted from its normal position to an outer seat 30. The vent valve stem 1d is thus lifted from its seat and liuid from the train pipe is vented to the atmosphere through port 16, to produce quie; serial action throughout the train. The position of the parts is noiv as shown in Fig. f5, from Which it Will be noted that although the abutment 9 is seated, the piston 17 is still away from the seat 19. Fluid therefore continues to flow from the train pipe and the pressure in chamber 12 correspondingly reduces, but the pressure in chamber 10 is practically bottled up, and as this higher pressure acts on the differential area 241. of the piston 17, upona predetermined reduction in train pipe pressure, dependent mainly on the extent of the differential area exposed to the pressure of chamber 10, said pressure together With the reduced train pipe pressure, Which now enters through the restricted passage 29 and acts on the seated area of piston 17, is suicient to lift the piston from its seat 18. The full area of the piston 17 is then exposed to the pressure in chamber 10 and the piston is thereupon quickly shifted to its outer seat 19, closing communication from chamber 12 to the train pipe, as shovvn in Fig. l of the drawing. rlhe fluid pressure in chamber 12 is noW bottled up, While fluid from chamber 10 escapes through the openings 25 and around the end of piston 17 to the passage 29 and the atmosphere. The pressure in chamber 12 consequently soon exceeds the pressure on the opposite side of the abutment and the same is then shifted to close the train pipe vent port and shut ott the further flow of air from `the train pipe. Upon closing the vent port, the interior of piston 17 is connected directly to the atmosphere through the restricted passage 29 and consequently the reduced ytra-in pipe pressure acting on the face of the piston eX- posed to the pressure in chamber 8 immediately shifts the piston to its normal position.

In charging up the system, as the chamber 10 is supplied with air only at the rate at which air can leak around the stem 14, it will be seen that danger of overcharging at the head end of the train is obviated',` and this is quite important, as in such case undesired action of the vent valve mechanism might take place upon the reduction of the tainpipe pressure to the normal pressure.

As the action of the vent valve is dependent on means adapted to operate independently of the vent valve, a much more reliable operation of the mechanism is assured.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a duid pressure brake, the combination with a train pipe, of a movable abut- I ment subject on one side to train pipe pres-V sure and on the opposite side to the `pressure of a chamber normally charged to train pipe pressure, a valve operated by said abutment upon a sudden reduction in train pipe pressure for opening a train pipe vent port, and means for closing communication from .the train pipe to .said abutment uponl a predetermined reduction in train pipe pressure.

2. 1n a fluid pressure brake, the combination With atrain pipe, of a movable abutment subject on one side to train pipe pressure and on the opposite side to the pressure of a chamber normally charged to train pipe pressure, a valve operated by said abutment upon a sudden reduction in train pipe pressure for opening a train pipe vent port, and means subject to the opposing pressures of the train pipe and said chamber and operating upon a predetermined reduction in train pipe pressure by flovv to the vent port for closing communication from the train pipe to said abutment.

3. In a fluid pressure brake, the combination With a train pipe, of a movable abutment subject on one side to train pipe pressure and on the o-pposite side to the pressure of a chamber normally charged to train pipe pressure, a valve operated by said abutment upon a sudden reduction in train pipe pressure for opening a train pipe vent port, and a piston device subject on one side to the pressure of fluid flowing from the train pipe to the vent port and to the pressure of said chamber and on the opposite side `to train pipe pressure and operating upon a predetermined reduction in train pipe pressure by flow to the vent port to close communication from the train pipe to said abutment.

4c. In a fluid pressure brake, the combination With a train pipe, of a movable abutment subject on one side to train pipel pressure and on the oppositeside to the pressure of a chamber normally charged to train pipe pressure, a valve operated by said abutment upon a sudden reduction in train pipe pressure for opening a train pipe vent port,

and a piston device subject on one side on a portionof its area to the pressure of fluid flovving from the `train pipe through the vent port andon another portion of its area to the pressure in said chamber, and on the opposite side to train pipe pressure, for controlling communication from the train pipe to said abutment, said piston device being operated by the chamber pressure acting on `one side to close said communication upon a predetermined reduction in train pipe pressure by flovv through the vent port.

5. In a fluid pressure brake, the combination with a train pipe, of a vent valve mechanism comprising a valve and movable abutment operating upon a sudden reduction in train pipe pressure for locally venting the train pipe and means for closing communication from the train pipe to said abutment upon a predetermined reduction in train pipe pressure.

6. A train pipe vent valve device comprising a casing, a movable abutment therein subject to the opposing pressures of the train pipe and a chamber, a valve operated by said abutment for controlling a vent port from the train pipe, and a piston carried by said abutment and subject to the opposing pressures of' the train pipe and said chamber for controlling communication from the train pipe to said abutment, said piston being adapted upon movement to close said. communication and to open communication for permitting the release of iuid from said chamber.

7. A train pipe vent valve device comprising a cas1ng,a movable abutment therein sub- ]ect to the opposing ressures to two chambers normally charge to train pipe pressure, a

a valve operated by said abutment upon a sudden reduction in pressure in one chamber for opening a train pipe vent port, a piston subject to the opposing pressures of' `said chambers for controlling communication from one chamber to the train pipe and operating upon a predetermined reduction in train pipe pressure by venting of fluid to said vent port for closing said communication, and means controlled by said piston for opening communication to permit release of fluid from the other chamber, to thereby effect the closing of the vent valve.

8. In a fluid pressure brake, the combination with a train pipe and a vent valve device operating upon a sudden reduction in train pipe pressure to vent air from the train pipe to the atmosphere, of a valve mechanism adapted, upon a predetermined reduction in train pipe pressure by the operation of the vent valve device, to efi'ect the closure of said vent valve device and thereby cut ofi the escape of air from the train pipe.

In testimony whereof I have hereunto set my hand.

WALTER V. TURNER.

Copies of this patent maybe obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

